Scrotal ultrasound:  This test uses high-frequency sound waves to produce images inside your body. A scrotal ultrasound can help your doctor see if there is a varicocele or other problems in the testicles and supporting structures.

Hormone testing:  Hormones produced by the pituitary gland, hypothalamus and testicles play a key role in sexual development and sperm production. Abnormalities in other hormonal or organ systems might also contribute to infertility. A blood test measures the level of testosterone and other hormones.

Post-ejaculation urinalysis:  Sperm in your urine can indicate your sperm are traveling backward into the bladder instead of out your penis during ejaculation (retrograde ejaculation).

Genetic tests:  When sperm concentration is extremely low, there could be a genetic cause. A blood test can reveal whether there are subtle changes in the Y chromosome — signs of a genetic abnormality. Genetic testing might be ordered to diagnose various congenital or inherited syndromes.

Testicular biopsy:  This test involves removing samples from the testicle with a needle. If the results of the testicular biopsy show that sperm production is normal your problem is likely caused by a blockage or another problem with sperm transport.

However, this test is not commonly used to diagnose the cause of infertility.​

Transrectal ultrasound:  A small, lubricated wand is inserted into your rectum. It allows your doctor to check your prostate, and look for blockages of the tubes that carry semen (ejaculatory ducts and seminal vesicles).